Social work is helping activities guided by scientific theories, so it can be significantly affected by different theories. To be more specific, conservative theories incline to attribute clients’ misery to individual level, such as personality, psychology and will, then to achieve personal treatment by behavior modification and psychological instruction. On the contrary, critical theories regard social structures as the origin of clients’ dilemma, and advocate to promote social reform by collective actions. Although both conservative and critical theories are applied to social work practice, the personal therapy guided by conservative theories(psychological theories, etc) is in dominant position, social reform led by critical theories is marginalized. The reason is, on the one hand, psychological and micro theories can easily translate abstract viewpoints into concrete therapeutic models, which can be accepted by social work effectively. On the other hand, individualistic attribution of conservative theories is consistent with western liberalism and individualism, so it can be supported by ruling class.